1. Field of the Invention
The present invention relates to a portable extension memory storage device, and more particularly to a portable extension memory storage device that can be engaged assuredly and firmly, and can improve convenience in use.
2. Description of the Prior Art
Referring to FIGS. 1-4, a combined structure for a portable memory device disclosed in Taiwan Patent No. 549496 comprises a memory body 10 and a shell 20. The memory body 10 consists of two mated half-shells that are fixed together by a threaded element 30. The memory body 10 has a head portion 11 at one end thereof and an adaptor 12 at the other end thereof. The memory body 10 is further provided with two opposite protruding blocks 13 at two opposite sides thereof. The shell 20 is slidably engaged on the memory body 10. The shell 20 is interiorly provided with two stopping plates 21 protruding toward the memory body 10. The shell 20 slides relative to the memory body 10 and is limited by the two protruding blocks 13 at two sides of the memory body 10. The memory body 10 is further provided with two opposite semicircular guide blocks 14 and two opposite trapezoidal guide blocks 15 on a sliding path of the stopping plates 21 relative to the protruding blocks 13. The semicircular guide blocks 14 are located adjacent to the protruding blocks 13, and the trapezoidal guide blocks 15 are located adjacent to the head portion 11. The stopping plates 21 of the shell 20 are guided by the semicircular guide blocks 14 and then limited between the semicircular guide blocks 14 and the protruding blocks 13, as shown in FIG. 1, at this moment, the shell 20 encloses the adaptor 12, forming a state of storage. When the shell 20 slides toward the head portion 11, the stopping plates 21 will be guided by the trapezoidal guide blocks 15 and then limited between the trapezoidal guide blocks 15 and the head portion 11, as shown in FIG. 2, at this moment, the shell 20 is abutted against the head portion 11 to expose the adaptor 12 for use. In addition, the memory body 10 is provided with a guide protrusion 16, and the shell 20 is interiorly provided with a slide 22 corresponding to the guide protrusion 16. As shown in FIGS. 3 and 4, the guide protrusion 16 slides along the slide 22 to make the memory body 10 slide relative to the shell 20.
However, the shell 20 is positioned at two different positions by utilizing the semicircular guide blocks 14 and the trapezoidal guide blocks 15 to guide the two stopping plates 21. The stopping plates 21, the semicircular guide blocks 14 and the trapezoidal guide blocks 15 are all made of hard material, so that the stopping plates 21 can pass across the guide blocks 14, 15 only by a slight deformation of the shell 20. Therefore, it can be found that abrasion inevitably occurs when the stopping plates 21 of the shell 20 pass across the respective guide blocks 14, 15, and after a long time of use, the stopping plates 21 can not be substantially positioned by the respective guide blocks 14, 15, so that the shell 20 can be easily disengaged from the memory body 10. Therefore, when the adaptor 12 of the memory body 10 is inserted into or removed from a computer, the user must hold the shell 20 to apply fore, but since the shell 20 cannot be positioned substantially relative to the memory body 10, the user cannot successfully insert or remove the memory body 10, thus causing much inconvenience.
In addition, due to abrasion of the memory body 10 and the shell 20, the service life of the memory device is greatly reduced.
Furthermore, besides oppositely mating the two half-shells, the assembling process for the memory body 10 further includes using the threaded element 30 to lock the memory body 10. Therefore, the assembling process for the memory body 10 is more complicated, and the number of the assembling parts is increased, thus relatively increasing the production cost.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.